Aqueous dispersion of flame retardant for textiles and process for producing same

ABSTRACT

Flame retardant aqueous dispersions or suspensions comprising tris(tribromophenoxy)-s-triazine (TTBT) or tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBBPE) or a mixture thereof and one or more nonionic or anionic surface active agent(s) and/or wetting agent(s) used in textile are described. The flame retardants exhibit high compatibility with textile materials and are stable in aqueous solutions.

FIELD OF THE INVENTION

The present invention relates to flame retardant aqueous dispersionsthat are used in textile. More particularly, the invention relates tothe use of flame retardants which exhibit a high compatibility withtextile materials and which are stable in aqueous solution.

BACKGROUND OF THE INVENTION

Flame retardation of textiles using aromatic bromine-containingformulations adhered to the substrates by means of binders, has beenlong established (for instance, U.S. Pat. No. 3,955,032 and U.S. Pat.No. 4,600,606). The main drawbacks of existing formulations include highbromine content demand, high dry add-on demand, streak marks on darkfabrics, excessive dripping during combustion of thermoplastic fibersand dispersion instability. Most of these drawbacks are inherent to thearomatic bromine compounds used.

Using existing aromatic bromine containing formulations, the percentageresin component may be as high as 60-70 wt % of the total add-on inorder to obtain satisfactory flame retardation (see Toxicological Risksof Selected Flame-Retardant Chemicals (2000), by Donald E. Gardner(Chair) Subcommittee on Flame-Retardant Chemicals, Committee onToxicology, Board on Environmental Studies and Toxicology, NationalResearch Council page 507). This high add-on is due in part to the largeamount of binder needed to fix the flame retardant (FR) agents to thetextile. The binder may be as high as 50 wt % of the total FRformulation (see Toxicological Risks of Selected Flame-RetardantChemicals (2000) page 507). Due to its substantial presence, the bindercontributes to flammability and dripping, which requires more brominecontent, thus creating an inefficient cycle. In order to obtain flameretarded textiles with better performance and less detriment to textileproperties, an efficient FR agent conducive to incorporation in lowbinder content formulations with good dispersion properties is required.

Tris(tribromophenoxy)-s-triazine (FR-245) is a flame retardant with acombination of aromatic bromine and cyanurate that provides high FRefficiency and good thermal stability. In its non-micronized form it isuseful in many applications, especially but not exclusively, in thefield of fire retardants for plastic compositions. FR-245 is insolublein water but has a specific gravity of about 2.4, significantly lowerthan bromine rich FR agents commonly used in such applications such asDecabromodiphenyl Oxide (Deca), which has a specific gravity of 3.FR-245 is also easily micronized. Therefore, FR-245 lends itself to thepreparation and use of more stable aqueous dispersions. FR-245 also hasa higher initial decomposition temperature than Decabromodiphenyl oxide.

Tetrabromobisphenol A bis(2,3-dibromopropyl ether) (FR-720) is a flameretardant with a combination of aromatic and aliphatic bromine thatprovides high FR efficiency and good thermal stability. FR-720 is usefulin many applications, especially but not exclusively, in the field offire retardants for plastic compositions. FR-720 is insoluble in waterbut has a specific gravity of about 2.3, significantly lower thanbromine rich FR agents commonly used in such applications such asDecabromodiphenyl Oxide (Deca). FR-720 has an advantage in that ahomogenous film can be achieved during the application due to its lowmelting range (113-117° C.) which enables melt penetration of thematerial being processed.

It has now been surprisingly found, and this is an object of the presentinvention, that two specific aromatic flame-retardants, never testedbefore in textile, possess unexpected stability and compatibilityproperties, which render them highly efficient for the purpose offlame-retarding textile materials.

It is thus a purpose of this invention to provide stable dispersions orsuspensions of A) tris(tribromophenoxy)-s-triazine or B)tetrabromobisphenol A bis(2,3-dibromopropyl ether), or of mixturesthereof, which alleviate the drawbacks of existing formulations fortreating textile materials.

It is another purpose of this invention to provide such dispersions orsuspensions that are aqueous dispersions or suspensions and which do notrequire non-aqueous solvents.

It is a further purpose of this invention to provide a process forpreparing such aqueous dispersions or suspensions.

It is yet another purpose of the invention to provide dispersions oftris(tribromophenoxy)-s-triazine or tetrabromobisphenol Abis(2,3-dibromopropyl ether) or of a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) for particular uses in the textile industryby coating and/or padding and/or foaming and/or spraying application.

It is still a further purpose of the invention to provide dispersions oftris(tribromophenoxy)-s-triazine or tetrabromobisphenol Abis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) together with additional compounds, such assynergists for increasing the fire-retarding efficiency of compositionsobtained from these flame retardants.

It is still another purpose of the invention to provide dispersions oftris(tribromophenoxy)-s-triazine or tetrabromobisphenol Abis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) with significantly reduced amounts ofbinder content.

It is also a purpose of the invention to produce a smooth, translucentcoating of tris(tribromophenoxy)-s-triazine or tetrabromobisphenol Abis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) on textile materials, when applied inaqueous solution.

Other purposes and advantages of the invention will become apparent asthe description proceeds.

SUMMARY OF THE INVENTION

The dispersion of tris(tribromophenoxy)-s-triazine ortetrabromobisphenol A bis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether), according to the invention, ischaracterized in that it comprises one or both of the above flameretardants, or mixtures thereof, and contains nonionic or anionicsurface-active agents or wetting agents.

The nonionic or anionic surface-active agents or wetting agents usefulin the invention are well known in the art and can be chosen by theskilled person without the need for experimentation. Illustrative andnon-limitative examples of nonionic agents include, for instance,polyoxyethylene (POE) alkyl ether type, preferably NP-6 (Nonylphenolethoxylate, 6 ethyleneoxide units).

Illustrative and non-limitative examples of anionic agents include, forinstance, free acids or organic phosphate esters or the dioctyl ester ofsodium sulfosuccinic acid.

The dispersion of the invention may also include other additives whichfunction both as dispersing agents and suspending agents and which arecommonly used by persons skilled in the art, such as acrylicacids/acrylic acids ester copolymer neutralized—sodium polycarboxyl,preferably naphthalene sulfonic acid—formaldehyde condensate sodiumsalt.

The suspension according to the invention may also include defoaming orantifoaming agents, which are well known to persons skilled in the art.These may include, for example, emulsion of mineral oils or emulsion ofnatural oils or preferably emulsion of silicon oils like AF-52™.

The suspension according to the invention may also include binderagents, which are well known to persons skilled in the art. These mayinclude, a polymer latex emulsion comprising of any acrylic co-monomers.For example, acrylic acid and methacrylic acid or their derivatives suchas esters, nitrites and amides can be employed. The esters are preferredcompounds. Specific examples of the acrylates that can be utilized aremethyl acrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate,propyl methacrylate, butyl acrylate, isobutyl acrylate, isobutylmethacrylate, amyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate,vinyl acrylate, allyl acrylate, hydroxyethyl acrylate, perfluoroethylacrylate, isobornyl acrylate, phenoxyethyl acrylate, tetraethyleneglycol diacrylate, tripropylene glycol diacrylate, trimethylolpropanetriacrylate, stearyl acrylate or stearyl methacrylate, acrylamide,methacrylamide, N—(C₁-C₈-alkyl acrylamides or—methacrylamides. A singleacrylate or various combinations of acrylates can be employed in makingthe copolymers. In addition, other co-monomers may be employed in thecopolymer latex including vinyl esters of saturated C₁-C₁₈-carboxylicacids, such as vinyl acetate, vinyl propionate, vinyl butyrate or vinylstearate, styrene, phenoxyethyl acrylate, hydroxyalkylene monoacrylicesters and hydroxyalkylene monomethacrylic esters or acrylic esters andmethacrylic esters of ethoxylated C₁-C₁₈-alcohols.

Other suitable illustrative textile binders areAcrylonitile-Butadiene-Styrene Copolymer, Polychloroprene Rubber andCarboxylated styrene butadiene rubber Polyurethane

Preserving or stabilizing agents such as formaldehyde, and preferably amixture of methyl and propyl hydroxy benzoates, can also be added to thedispersion.

According to a preferred embodiment of the invention, dispersions oftris(tribromophenoxy)-s-triazine or tetrabromobisphenol Abis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) are mixed together with additionalcompounds—such as fire-retardant synergists, e.g. fire-retardantantimony oxide (AO).

According to another preferred embodiment of the invention dispersionsof tris(tribromophenoxy)-s-triazine or tetrabromobisphenol Abis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) are incorporated in formulations withtypically 30% or less, preferably 27% or less binder by weight.

According to still another preferred embodiment of the invention,formulations of tris(tribromophenoxy)-s-triazine or tetrabromobisphenolA bis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) are used to impart satisfactory flameretardancy to textiles with less than 60% dry add-on, preferably 50% dryadd-on, most preferably with 40% dry add-on by weight.

According to yet another preferred embodiment of the inventionformulations of tris(tribromophenoxy)-s-triazine or tetrabromobisphenolA bis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) are used to impart satisfactory flameretardancy to textiles after washing with detergent.

According to a preferred embodiment of the invention formulations oftris(tribromophenoxy)-s-triazine or tetrabromobisphenol Abis(2,3-dibromopropyl ether) or a blend oftris(tribromophenoxy)-s-triazine and tetrabromobisphenol Abis(2,3-dibromopropyl ether) are used to impart a smooth, translucent,non streaky coating on the textile substrates.

The dispersions, in particular the aqueous dispersions, of the inventionare stable. When stored at room temperature, they are stable for atleast two weeks and preferably at least one month. Their stability maybe higher, e.g. three months or more.

The above and other characteristics and advantages of the invention willbe better understood through the following illustrative andnon-limitative detailed description of preferred embodiments thereof,with reference to the following examples.

EXAMPLE 1 Preparation of a Dispersion ofTris(Tribromophenoxy)-s-triazine (FR-245)

248 gr. of FR-245 with a size distribution ranging from 0.1 micron to 20microns was added drop-wise to a mixed solution of 164 gr. of deionizedwater and 25 gr. of dispersing agent. 100 gr. Sb₂O₃ was added to themixed dispersion. The dispersion was allowed to mix for fifteen minutes.About 5 gr. of acrylic thickener was added during mixing and thedispersion was neutralized to pH=7 using ammonium hydroxide. Thecomposition of the dispersion is detailed in Table I below.

TABLE I Dispersion Viscosity (cP) 40 000    PH 7  FR in dispersion (wt%) 45.8 Br in dispersion (wt %) 30.7 Sb₂O₃ in dispersion (wt %) 18.5

The FR-245 dispersion was smooth, white and had good fluidity. Thedispersion was left on a shelf for 6 months and remained stable (nosettling was observed) during this period.

EXAMPLE 2 Preparation of a Formulation of FR-245

58 gr. of deionized water and 58 gr. of acrylic binder were added to 79gr. of dispersion from Example 1. 19 gr. of acrylic thickener was addedwhile mixing and the dispersion was neutralized to pH=7-8 using ammoniumhydroxide. Details of the dispersion are given in Table II below.

TABLE II Dispersion Viscosity (cP) 28000 PH 7-8 FR in dispersion (wt %)16.8 Br in dispersion (wt %) 11.3 Sb₂O₃ in dispersion (wt %) 6.8

This formulation contained 27% by weight of binder, 16.8 wt % FR agentand 11.3 wt % bromine content. The FR-245 formulation was smooth, whiteand had good fluidity. The dispersion was left on a shelf for 6 monthsand remained stable (no settling was observed) during this period.

EXAMPLE 3 Application of FR-245 Formulation to Polyester Fabric

Polyester fabric weighing 164 grams per square meter was coated using aknife coater with the formulation from Example 2 to 57.7% dry add-on andcured. The fabric passed ASTM D 6413-99 with negligible dripping. Thefabric was translucent with no visible streak marks.

EXAMPLE 4 Application of FR-245 Formulation to Polyester Fabric

Polyester fabric weighing 164 grams per square meter was coated using aknife coater with the formulation from Example 2 to 40% dry add-on andcured. The fabric passed ASTM D 6413-99 with negligible dripping. Thefabric was translucent with no visible streak marks.

EXAMPLE 5 Application of FR-245 Formulation to Polyester Fabric

Polyester fabric weighing 164 grams per square meter was coated using aknife coater with the formulation from Example 2 to 40% dry add-on andcured. The fabric was washed with 1 gram per liter standard detergent at80° C. for 30 minutes and dried. The fabric passed ASTM D 6413-99 withnegligible dripping. The fabric was translucent with no visible streakmarks.

EXAMPLE 6 Preparation of a Dispersion of Tetrabromobisphenol Abis(2,3-dibromopropyl Ether) (FR-720)

248 gr. of FR-720 was added drop-wise to a mixed solution of 241 gr. ofdeionized water and 36 gr. of dispersing agents. 100 gr. Sb₂O₃ was addedto the mixed dispersion. The dispersion was allowed to mix for fifteenminutes. About 7.3 gr. of acrylic thickener was added during mixing andthe dispersion is neutralized to pH=7 using ammonium hydroxide. Detailsof the dispersion are given in Table III below.

TABLE III Dispersion Viscosity (cP) 40 000    PH 7  FR in dispersion (wt%) 39.2 Br in dispersion (wt %) 26.5 Sb₂O₃ in dispersion (wt %) 15.8

The FR-720 dispersion was smooth, white and had good fluidity. Thedispersion was left on a shelf for 6 months and remained stable (nosettling was observed) during this period.

EXAMPLE 7 Preparation of a Formulation of FR-720

140 gr. of deionized water and 145 gr. of acrylic binder were added to198 gr. of dispersion from Example 6. 18.4 gr. of acrylic thickener wasadded during mixing and the dispersion was neutralized to pH=7-8 usingammonium hydroxide. Details of the dispersion are given in Table IVbelow.

TABLE IV Dispersion Viscosity (cP) 16400 PH 7-8 FR in dispersion (wt %)15.9 Br in dispersion (wt %) 10.7 Sb₂O₃ in dispersion (wt %) 6.4

This formulation contained 34.2% by weight of binder, 15.9% FR agent and10.7% bromine content. The formulation was smooth, white and had goodfluidity. The dispersion was left on a shelf for 6 months and remainedstable (no settling was observed) during this period.

EXAMPLE 8 Application of FR-720 Formulation to Polyester Fabric

Polyester fabric weighing 164 grams per square meter was coated using aknife coater with the formulation from Example 7 to 35% dry add-on andcured. The fabric passed ASTM D 6413-99 with negligible dripping. Thefabric was translucent with no visible streak marks.

EXAMPLE 9 Preparation of a Dispersion of FR-245/FR-720 Blend

248 gr. of FR-245/FR-720 1:1 blend was added drop-wise to a mixedsolution of 315 gr. of deionized water and 25 gr. of dispersing agent.100 gr. Sb₂O₃ was added to the mixed dispersion. The dispersion wasallowed to mix for fifteen minutes. About 6.6 gr. of acrylic thickenerwas added during mixing and the dispersion was neutralized to pH=7 usingammonium hydroxide. Details of the dispersion are given in Table Vbelow.

TABLE V Dispersion Viscosity (cP) 40 000    PH 7  FR in dispersion (wt%) 35.7 Br in dispersion (wt %) 23.9 Sb₂O₃ in dispersion (wt %) 14.4

The FR-245/FR-720 1:1 blend dispersion was smooth, white and had goodfluidity. The dispersion was left on a shelf for 6 months and remainedstable (no settling was observed) during this period.

EXAMPLE 10 Preparation of a Formulation of FR-245/FR-720 Blend

145 gr. of deionized water and 145 gr. of acrylic binder were added to198 gr. of dispersion from Example 9. 17 gr. of acrylic thickener wasadded during mixing and the dispersion was neutralized to pH=7-8 usingammonium hydroxide. Details of the dispersion are given in Table VIbelow.

TABLE VI Dispersion Viscosity (cP) 9600 PH 7-8 FR in dispersion (wt %)13.7 Br in dispersion (wt %) 9.2 Sb₂O₃ in dispersion (wt %) 5.5

This formulation contained 38% by weight of binder, 13.7% FR agent and9.2% bromine content. The FR-245/FR-720 1:1 blend formulation wassmooth, white and had good fluidity. The dispersion was left on a shelffor 6 months and remained stable (no settling was observed) during thisperiod.

EXAMPLE 11 Application of FR-245/FR-720 Blend Formulation to PolyesterFabric

Polyester fabric weighing 164 grams per square meter was coated using aknife coater with the formulation from Example 10 to 44% dry add-on andcured. The blend film was transparent and soft. The fabric passed ASTM D6413-99 with negligible dripping. The fabric was translucent with novisible streak marks.

While examples of the invention have been described for purposes ofillustration, it will be apparent that many modifications, variationsand adaptations can be carried out by persons skilled in the art,without exceeding the scope of the claims.

The invention claimed is:
 1. An aqueous flame retarding dispersionuseful for imparting a smooth, translucent, and non streaky coating totextiles, and for providing a satisfactory flame retardancy (accordingto ASTM D 6413-99 or other applicable standards) with less than 60% dryadd-on by weight of said textile, said dispersion consisting of: a) aflame retardant selected from among tris(tribromophenoxy)-s-triazine,tetrabromobisphenol A bis(2,3-dibromopropyl ether), and a mixturethereof; b) one or more flame-retardant synergist(s); c) one or morenonionic or anionic surface-active agent(s) and/or wetting agent(s); andd) one or more polymeric binder(s) selected from the group consisting ofpolymer latex emulsions of co-monomers selected from the groupconsisting of acrylic acids and their esters, nitrite and amidederivatives, methacrylic acids and their esters, vinyl esters ofsaturated C1-C8-carboxylic acids, styrenes, and any combinationsthereof; ii) vinyl esters of saturated C₁-C₁₈-carboxylic acids; iii)styrenes; iv) copolymer of acrylonitrile-butadiene-styrene; v)polychloroprene rubber; vi) carboxylated styrene butadiene rubber; vii)polyurethanes; and viii) any combinations thereof; wherein saiddispersion contains 30% or less of said polymeric binder(s) by weight.2. The dispersion of claim 1, wherein the nonionic surface-active agentis selected from the group consisting of polyoxyethylene (POE) alkylether type, nonylphenol ethoxylate, 6 ethyleneoxide units (NP-6), freeacids or organic phosphate esters, dioctyl ester of sodium sulfosuccinicacid, and combinations thereof.
 3. The dispersion of claim 1, whereinthe flame-retardant synergist is antimony oxide.
 4. The dispersion ofclaim 1, wherein the acrylic acid and methacrylic acid co-monomers areselected from the group consisting of methyl acrylate, ethyl acrylate,ethyl methacrylate, propyl acrylate, propyl methacrylate, butylacrylate, isobutyl acrylate, isobutyl methacrylate, amyl acrylate,2-ethylhexyl acrylate, cyclohexyl acrylate, vinyl acrylate, allylacrylate, hydroxyethyl acrylate, perfluoroethyl acrylate, isobornylacrylate, phenoxyethyl acrylate, tetraethylene glycol diacrylate,tripropylene glycol diacrylate, trimethylolpropane triacrylate, stearylacrylate stearyl methacrylate, acrylamide, methacrylamide,N—(C₁-C₈)-alkyl acrylamides, N—(C₁-C₈)-alkyl methacrylamides,phenoxyethyl acrylate, hydroxyalkylene monoacrylic esters of ethoxylatedC₁-C₈ alcohols, hydroxyalkylene monomethacrylic esters of ethoxylatedC₁-C₈ alcohols, acrylic esters of ethoxylated C₁-C₈ alcohols, andmethacrylic esters of ethoxylated C₁-C₈ alcohols acrylic esters ofethoxylated C₁-C₁₈ alcohols, methacrylic esters of ethoxylated C₁-C₁₈alcohols and; co-monomers of two or more of said acrylic and methacrylicacid co-monomers, and wherein when the polymeric binder is vinyl estersof saturated C₁-C₁₈-carboxylic acids, then the co-monomers are selectedfrom the group consisting of vinyl acetate, vinyl propionate, vinylbutyrate, and vinyl stearate.
 5. The dispersion of claim 1, wherein saiddispersion comprises 27% or less polymeric binder(s) by weight.